Polyethyleneglycols as laundering aids



United States Patent() assiguors to the United States of America theSecretary of Agriculture Willie Fong,

ley, Califi, as represented by No rawing. Application December 5, 1952,Serial No. 324,422

2 Claims. (Cl. 252-461) (Granted under Title 35, U. S. Code (1952), see.266) A non-exclusive, irrevocable, royalty-free license in the inventionherein described, for all governmental purposes, throughout the world,with the power to grant sublicenses for such purposes, is hereby grantedto the Government of the United States of America.

This invention relates to washing procedures particularly to the washingof textile materials such as fabrics and fibers with aqueous media. Inparticular the invention concerns the use of polyethyleneglycol in theaqueous washing medium whereby to minimize the re-deposition of soilduring the washing procedure.

It is well known in the art that a successful Washing operation involvestwo separate factors, i. e., (a) the removal of dirt from the textilematerial and (b) keeping the soil suspended in the medium so that itwill not be re-deposited on the textile. In general aqueous Washingmedia containing soap fulfill both of these criteria as soap not only isa good soil remover but also keeps the removed soil in suspension sothat little re-deposition takes place. However, the present trend istoward the use of anionic synthetic detergents such as the alkyl benzenesulphonates since these agents can be used in hard water areas as theirdetersive power is not decreased by the presence of calcium andmagnesium ions. However, these anionic detergents have the disadvantagethat their suspending power is poor. Whereas they are very effectivefrom the standpoint of removing soil they are not so efiective inpreventing re-deposition and so cotton fabrics washed with such agentswill be grayer than when using soap. In order to overcome thisdisadvantage, various soil suspending agents are commonly added to theanionic detergents. One of the most commonly used agents is sodiumcarboxymethyl cellulose.

It has now been found that polyethyleneglycol has useful soil-suspendingproperties and when added to aqueous washing media the degree of soilre-deposition is greatly reduced. As Well known in the art,polyethyleneglycol is not a single, individual compound but may beobtained in almost any degree of polymerization. The degree ofpolymerization is most easily expressed in terms of average molecularweight. Although this invention comprises in its broad aspect the use ofpolyethyleneglycol having any degree of polymerization and which issoluble in water at least to the extent of about .001% to about 0.1%, itis to be understood that not all the polymers possess the same degree ofeffectiveness. Thus polyethyleneglycols having an average molecularweight from about 1,000 to about 10,000 exhibit maximum soil-suspendingactivity. For this reason it is preferred to use a polyethyleneglycol ofsuch molecular weight range as a soil-suspending agent in washingoperations.

In applying this invention in practice the polyethyeneglycol may bedispersed into the aqueous washing medium in a concentration from about0.001% to about 0.1%, the higher proportions giving the greater degreeof protection against soil redeposition. It is obvious that theproportion of polyethyleneglycol can be higher than the above ice 'range but in' general increasing the concentration above 0.1% giveslittle if any added protection. If desired, the polyethyleneglycol canbe incorporated with the detergent so as to form a composition which ondissolving in water furnishes the desired washing medium. To this end,the detergent is mixed with about 2 to 10% of the aforesaidsoil-suspending agent.

In carrying out washing operations in accordance with this invention,the fabric or other textile material is agitated in the usual'mannerpreferably at elevated temperatures as commonly used in laundries withthe aqueous media containing the polyethyleneglycol and the detergent.As the detergent one may use any of the materials commonly used forwashing purposes.

The detergent may be, for example, of the anionic'or non-ionic types. Inthe first category are included ordinary soaps, that is, sodium orpotassium salts of the higher fatty acids, or usually, mixtures ofhigher fatty acids as are present in naturally occurring oils and fats.Also included in the anionic category are the detergents of thesulphonate or sulphate type. As well known in the art, a multitude ofsuch materials are available, including the alkyl (C8Cl8) sulphates, thealkyl (Cs-C13) sulphonates, the alkyl (Cs-C18) aromatic sulphonates, themonoor di-alkyl (Cs-C13) esters of sulphosuccinic acid, sulphonated orsulphated amides of the higher fatty acids such as N-sulphoethylstearamide, and so fourth. These compounds are generally employed in theform of their salts, i. e., their sodium, potassium, ammonium or aminesalts. Some of the particular detergents which may be used are: sodiumoctyl sulphate, sodium nonyl sulphate, sodium decyl sulphate, sodiumundecyl sulphate, sodium dodecyl sulphate, sodium tridecyl sulphate,sodium tetradecyl sulphate, sodium pentadecyl sulphate, sodium hexadecylsulphate, sodium heptadecyl sulphate, sodium octadecyl sulphate, sodiumoleyl sulphate, sodium octyl sulphonate, sodium nonyl sulphonate, sodiumdecyl sulphonate, sodium undecyl sulphonate, sodium dodecyl sulphonate,sodium tridecyl sulphonate, sodium tetradecyl sulphonate, sodiumpentadecyl sulphonate, sodium hexadecyl sulphonate, sodium octadecylsulphonate, sodium oleyl sulphonate, sodium salt of dioctyl sulphosuccinate, sodium octyl benzene sulphonate, sodium nonyl benzenesulphonate, sodium decyl benzene sulphonate, sodium undecyl benzenesulphonate, sodium dodecyl benzene sulphonate, sodium tridecyl benzenesulphonate, sodium tetradecyl benzene sulphonate, sodium pentadecylbenzene sulphonate, sodium hexadecyl benzene sulphonate, sodiumheptadecyl benzene sulphonate, sodium octadecyl benzene sulphonate,sodium tri (isopropyl) benzene sulphonate, sodium tri (isobutyl) benzenesulphonate, sodium tri (isopropyl) naphthalene sulphonate, sodium tn'(isobutyl) naphthalene sulphonate, and so forth. The commerciallyavailable detergents are generally not pure compounds but are mixturesof homologous compounds and are quite satisfactory. Thus for example,the sodium alkyl benzene sulphonate wherein the alkyl group contains 12to 18 carbon atoms is a Well known detergent. Others are: a mixture ofsodium alkyl sulphates consisting mostly of sodium lauryl sulphate; amixture of sodium alkyl phenol sulphonates wherein the alkyl groupcontains 12 to 18 carbon atoms; and a mixture of sodium alkylsulphonates wherein the alkyl group contains 10 to 18 carbon atoms. Asnon-anionic detergents one may employ polyalkylene glycol esters, ethersand thioethers of the following types:

wherein the Rs represent long chain alkyl radicals of 8 to 12 carbonatoms and n is an integer from about 4 to 12. Other non-anionicdetergents are the long-chain fatty acid esters of anhydrosorbitol, orthe polyethylene glycol addition products of such esters. It is evidentthat the particular detergent used is not critical except that oneshould be chosen which is generally useful in emulsitying and detergentapplications.

The concentration of the detergent is not critical within a wide rangeand depending on the soil removal etficiency of the particular agent,the range of concentration may be from about 0.05% to about 0.5%. Ifdesired, the soil removal efilciency of the detergent maybe increased byaddition to the aqueous medium of any of the usual types of builderssuch as sodium hexametaphosphate, tetrasodium pyrophosphate, sodiumtripolyphosphate, trisodium phosphate, borax, sodium carbonate, sodiumsilicate, sodium metasilicate, and so forth.

The following examples illustrate the invention in greater detail. Theknown soil-suspending agent, sodium carboxymethyl cellulose, wasemployed in some of the experiments for comparative purposes. In all theexperiments, carbon black was added to the washing media to test thesoil-suspending power of the various materials under test. Obviously inpractice of the invention, no carbon black or other soil would be addedto the washing medium.

' Example I A series of experiments were carried out in which cleanswatches of cloth were agitated in an aqueous media containing asynthetic detergent, various soil-suspending agents atvarious'concentration levels, and carbon black. The treated swatcheswere then subjected to reflectance measurements to measure the amount ofsoil (carbon black) which had been deposited on the fabric thus tocompare the effectiveness of the soil-suspending agents. The reflectancevalues are an index of the cleanness of the cloth; the higher theproportion of light reflected the cleaner the. cloth. The experimentswere carried out as follows:

A standard washing medium was prepared containing: water; sodium alkyl(C12C18) benzene sulphonate, 0.12%; sodium tripolyphosphate, 0.08%;sodium carbonate, 0.04%; and carbon black, 0.1%. The pH of this solutionwas about 10.3. To samples of the standard medium were added varioussoil-suspending agents as hereinafter indicated. Each solution soprepared was tested as follows:

Two hundred cc. of the test solution was placed in a pint jar togetherwith a swatch of a standard bleached muslin (cotton) cloth and 20%"stainless-steel balls.

The jar was then sealed and placed in a Launderometer and agitated byrotation at 140 F. for 20 minutes. The test swatch was then removed,rinsed 4 times with distilled water and agitated with 200 cc. ofdistilled water in the Launderometer for 10 minutes at 140 F. Thiswashing in distilled water was done to remove loosely adherent carbonblack so that the results would relate solely to adsorbed soil. Thetreated swatch was then dried in air, ironed, and the reflectancemeasured.

The materials and proportions used and the results obtained aretabulated below:

Reflectance (percent) of washed samples using various soil-suspendingagents at various concentration levels Concentration of soil-suspendingagent, Polyethylene Polyethylene- Polyethylene- Sodium percent glycol,glycol, glycol, carboxy- Average mol. average 1110]. average mol. methylWt. 6,000- wt. 1,300- wt. 380-420 cellulose The reflectance of theoriginal cloth sample was Having thus described our invention We claim:

1. A process for removing soil from a textile material and minimizingthe re-deposition of removed soil which comprises washing the materialwith a solution comprising water, about 0.05% to about 0.5% of a sodiumalkyl benzene sulphonate wherein the alkyl group contains 12 to 18carbon atoms, and a soil suspending agent consisting of about 0.001% toabout 0.1% concentration in said solution of a polyethyleneglycol havingan average molecular weight of 6,000 to 7,500.

2. A washing solution which is effective to remove soil from textilematerials and to minimize re-deposition of removed soil which compriseswater, about 0.05 to about 0.5% of sodium alkyl benzene sulphonatewherein the alkyl group contains 12 to 18 carbon atoms, and a soilsuspending agent consisting of about 0.001% to about 0.1% concentrationin said solution of a polyethyleneglycol having an average molecularweight of 6,000 to 7,500.

References Cited in the file of this patent UNITED STATES PATENTS bideand Carbon Chem. Corp., N. Y. (1946), page 9.

Synthetic Organic Chemicals, Carbide and Carbon Chem. Corp., N. Y., 12thed. (1945), pages l923.

1. A PROCESS FOR REMOVING SOIL FROM A TEXTILE MATERIAL AND MINIMIZINGTHE RE-DEPOSITION OF REMOVED SOIL WHICH COMPRISES WASHING THE MATERIALWITH A SOLUTION COMPRISING WATER, ABOUT 0.05% TO ABOUT 0.5% OF A SODIUMALKYL BENZENE SULPHONATE WHEREIN THE ALKYL GROUP CONTAINS 12 TO 18CARBON ATOMS, AND A SOIL SUSPENDING AGENT CONSISTING OF ABOUT 0.001% TOABOUT 0.1% CONCENTRATION IN SAID SOLUTION OF A POLYETHYLENEGLYCOL HAVINGAN AVERAGE MOLECULAR WEIGHT OF 6,000 TO 7,500.